Continuous casting apparatus



April 9, 1957' J. B. BRENNAN CONTINUOUS CASTING APPARATUS Filed Nov. l5. 1953 Lil...

R. Y ON E mw MAN WN e .1M

' CONTINUOUS CASTWG APPARATUS .loseph B. Brennan, Cleveland, @hie Application November 15, 1951, Seriai No. 256,568

4 Claims. (Cl. 22-57.4)

The present invention relates generally as indicated to a casting apparatus and has for one of its objects the provision of a casting apparatus having a die wherefrom the cast metal article is continuously discharged in the form of a rod, wire, strip, tube, or the like, the molten metal being fed incrementally into the die in metered 'amount to assure uniformity in the casting operation irrespective of variation in the pressure head and temperature of a molten metal pool from which the metal is transferred in metered amounts to the inlet of the die.

Another object is to provide an apparatus for casting which involves incrementally feeding molten metal into a die from which the metal casting is discharged in a shape-retaining form and at a uniform rate.

A more specific object is to provide a casting apparatus in which the molten metal from a supply pool is fed into pockets or the like in a rotary wheel which during rotation successively communicates the pockets thereof with the supply pool for filling of the pockets and transfers such charges of molten metal into an arcuate die through which the metal is carried by the wheel through casting and solidication zones. The solidiflcation zone is effective to cool the metal to a shape-retaining form and if desired this zone may include a cooled die wall Which moves in unison with the Wheel.

Other objects and advantages will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certainillustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in-which the principle of the invention may be employed.

in said annexed drawing:

Pig. l is a vertical cross-section view of one embodiment of the invention; and

Fig. 2 is a fragmentary vertical cross-section view illustrating a modication.

.Referring now more specifically to the drawing and rst to Fig. lithereof, the casting apparatus illustrated therein comprises a crucible l containing molten metal 2 therein, said Crucible being formed with an outlet passage 3. preferably at the bottom thereof. The molten metal 2 is maintained in a properly heated Condition as by means of the high frequency heating coil d and of course other equivalent heating means may be employed.

Below said Crucible 1 is a die block 5 which defines with a rotary wheel 6 a die passage 7 provided with an inlet S at one end for the introduction of molten metal thereinto. Said die block and said wheel 6 may be heated as by means of the high frequency heating coil 9 therearound. The lower portion of said block 5 is formed with passages lil for the circulation of coolant so as to eifect cooling of the metal as it flows and is advanced through the die passage 7 to a shape-retaining Patented Apr. 9, i957 ice form, such cooling being further continued and the die passage 7 being extended around the wheel 6 as by means of an endless relatively cool band 11 or the equivalent disposed concentric with the Wheel and having coolant sprays 12 or the like directed thereagainst. lf desired, cooling of the metal may be achieved by providing a pool of coolant liquid such as molten lead or other metal or alloy having a melting point less than that of the metal being cast, through which the wheel passes. As shown, said band 11 passes around a portion of the periphery of the wheel 6 and preferably said band moves in unison with the wheel to uniformly discharge or transfer the casting 13 from the end of the solidication zone of the die passage 7. The shape-retaining casting 13 in the form of one or more strips, rods, wires, tubes, or like elongated shapes shrunk onto the wheel and continuously Carried thereby to the outlet 1d and said casting may be further heat-treated or may be rolled as by means of the rollers 15 and wound up onto a take-up v reel le or be cut into desired lengths.

The wheel 6 has formed therein around the periphery a series of pockets or depressions 17 which during the rotation of the wheel pass successively under the Crucible outlet passage 3 for filling of such pockets with molten metal and then into communication with the inlet d to the die passage 7. The molten metal is introduced into the die passage 7 by: (l) the partial vacuum effect of the continuous discharge of the Casting lili from the passage 7; and/ or (2) in the event of high speed rotation of the wheel, by the slinging of the molten metal by centrifugal force from the pockets 17 into the die passage 7.

In the latter instance, the fluid motor ed'ect of the centrifugal force on the molten metal manifesting itself in a pressure acting on the solidified portion of the casting in the die passage 7v assists in the rotation of the wheel and in the ydischarge of the casting 13. ln any event, the volume of metal entering the pockets f7 is equal to the volume of the casting 13. The pockets 17 may be evacuated by passing under a vacuum chamber' l to facilitate rapid filling thereof, and it may be desirable to apply gas pressure to the molten metal supply pool 2 in the Crucible 1 so as to enable high speed operation of the castingapparatus, and in addition the application of gas pressure to the molten metal pool may have the effect of driving the wheel 6 in the manner of a rotor of a uid motor provided that the effective areas of the Wheel and Crucible in radial planes acted upon by the molten metal under pressure is unbalanced to drive said wheel.

The band 1l previously referred to may pass over rollers 1.9, one or more of which, preferably including the one adjacent the outlet 14, may be power-driven so as to drive said band at the same speed as the wheel.

The apparatus illustrated in Fig. l, and as just described, basically comprises a die passage 7 and means for inerementaliy supplying molten metal into such passage for flow through casting and solidication zones of suchV passage. Specifically, the means for incrementally supplying molten metal into the die passage comprises the pockets or depressions 17 of the wheel e which incrementally transfer predetermined volumes of molten metal 2 from the crucible 1 to the die passage, such metered supply of molten metal into the die passage assuring uniform casting performance regardless of some degree of variation in the head of the molten metal in Crucible l and in the temperature or viscosity of the metal so long as the pockets 17 are uniformly lilled each time that they pass under the Crucible outlet 3. While no means have been illustrated herein for supplying metal into the Crucible 1, it will be apparent to those skilled in the art that metal may be continuously charged into said crucible by suitable apparatus or the metal may simply be periodically ladled or otherwise supplied to said Crucible.

ln the modification illustrated in Fig. 2, the pockets or depressions 17 are in the form of a series of piston cylinder assemblies, the pistons 20 of which are successively retracted radially inwardly by a cam groove 21 engaging a laterally projecting pin 22 on each piston for filling of the cylinder of each with molten metal as the cylinder communicates with the crucible outlet 3. The cam groove 21 is of a shape such that when the filled pockets 17 communicate with the inlet 8 of the die passage 7, said pistons 20 are successively actuated radially outwardly to eject the molten metal into the die passage 7. Preferably the pistons 20 are moved radially out ward to a position fiush with the portion of the wheel which constitutes the inner movable wall of the die passage. In this way the ends of the pistons 20 define with the wheel a smooth inner ydie wall of the passage 7 at least in the solidification zone which starts at the bottom portion of the die block 5. Thus the form of the invention illustrated in Fig. 2 does not rely alone on centrifugal force or vacuum effect for emptying of the metered quantities of molten metal in the pockets 17 into the die passage 7.

In view of the foregoing, it is evident that the present apparatus and method enables continuous, accurate cast ing of molten metal into desired elongated shape-retainingr forms such as rods, wires, strips, tubes, or the like. It is to be understood that the entire apparatus or any portion thereof may be enclosed within a pressure chamber' or a vacuum chamber or a gas chamber containing a neutral atmosphere which eliminates oxidation of the molten metal and the casting produced therefrom. While in the apparatuses illustrated, only the outer wall of the die passage 7 is cooled for creating a solidification zone therein, it is contemplated that suitable cooling means such as sprays may be associated with the wheel 6 preferably near the inner periphery thereof so as to cool the peripheral wall of the wheel as it passes through the solidification zone. Otherwise it is desired to maintain the periphery of the wheel in a heated condition to the extent that the metal charged into the pockets or depressions 17 will not be unduly chilled while therein.

After the metal enters the die passage 7 it is carried along with the wheel (and preferably at the same speed) and the inner surface of the strip 13 adheres sufficiently to the outer contacting surface of the Wheel 7 and is chilled thereby so that it moves therewith.

in the drawings the cavities 7 are exaggerated in size for illustration purposes.

As aforesaid, the rollers 15 may be employed to smooth out irregularities, if any, in the strip 13 as might be left in some cases by the pockets or depressions 17.

While in the illustrated embodiments of the invention the molten metal is fed to the outside of the wheel, it is contemplated to reverse such feed, that is, to feed the molten metal from the inside of the Wheel. Thus, without necessity of separate illustration the passage 3 may lead to the inner portions of the pockets or depressions 17. As a further alternative, the molten metal may be transferred circumferentially and radially inward to a die passage having an inlet communicating with pockets or depressions 17 which are located radially outward of the die passage. This also is deemed to be a modification of such nature as not to require separate illustration.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. Apparatus for continuously casting metal comprising a Crucible having an opening for discharge of molten metal therefrom, an arcuate cooling die having an open inner side for fiow of molten metal thereinto and an open end from which metal therein is adapted to continuously issue in shape-retaining form, and a rotary wheel having its periphery radially spaced from said cooling die and having a series of circularly arranged cavities in its periphery which, yduring rotation of said wheel, first successively register with such opening for filling of successive cavities with molten metal and then successively register with the open side of said die for emptying of the molten metal from the successive cavities into said `die for solidication of the metal therein and for continuous withdrawal of the solidified metal from the open end of said die.

2. The apparatus of claim 1 wherein said cooling die extends around under such cavities whereby the metal is gravity-fed from the cavities into said die.

3. The apparatus of claim 1 wherein plungers are radially outwardly movable in auch cavities to displace the molten metal therefrom into said die, and cam means are engaged with said plungers to move the latter when the filled cavities are in register with the open side of said die.

4. The apparatus of claim 1 wherein a vacuum chamber, ahead of such opening, first registers with successive cavities during rotation of said wheel to evacuate such cavities prior to filling with molten metal.

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